Despite significant improvements in the management of ovarian cancer, approximately 13,900 women per year in the United States are expected to ultimately fail standard therapies and die. Peritoneal spread is the major route of dissemination and leads to significant morbidity. Therefore, ovarian cancer is well suited for the application of adenoviral anti-cancer treatments because they permit a regional administration of the vector into the peritoneal cavity with exposure of disseminated lesions to a locally high concentration of vector. However, a major disadvantage of current adenovirus vectors is that they efficiently transduce non-target, mesothelial cells that line all the major organs in the peritoneal cavity while inefficiently transducing ovarian cancer cells. This suboptimal efficiency and specificity results because the target cancer cells often do not express high levels of the primary adenovirus receptor, the Coxsackie-Adenovirus Receptor (CAR), while the non-target mesothelial cells are efficiently transduced in a CAR-dependent manner. We have made significant strides in increasing the specificity of adenovirus vectors for cancer applications. We have created two targeted adenovirus vectors that are simultaneously mutated to avoid binding to CAR and genetically redirected for binding to either alphavbeta3/5 or alphavbeta6 integrin receptors, which are both highly expressed in ovarian cancers. Our preliminary data indicates that these vectors will avoid CAR-mediated gene transfer to healthy mesothelial tissue while efficiently targeting tumor cells that express either alphavbeta3/5 or alphavbeta6 integrin receptors. Our overall objective in the proposed studies is to identify a targeted lead vector expressing the therapeutic transgene for tumor necrosis factor-alpha (TNF) for the treatment of ovarian cancer. This lead must demonstrate significant anti-tumor activity with an acceptable toxicity profile in at least 2 preclinical models designed to closely mimic the clinical application. We will first test the hypothesis that the in vitro and in vivo efficiency and specificity of gene delivery are improved through targeting using vectors carrying marker genes (Specific Aim 1). We will then construct alphavbeta3/5 or alphavbeta6 -targeted vectors carrying the transgene for TNF. We will test the feasibility of these vectors as clinical leads by determining whether they display appropriate anti-tumor activities and toxicity profiles according to predefined criteria (Specific Aim 2).